Biomedical Engineering Reference
In-Depth Information
Overall, magnetic nanomaterials have a combination of unique properties, such
as sensitivity in the nanomolar range, an ability to penetrate to the most unreach-
able remote parts of the tissue, and to be manipulated by an external magnetic
fi eld. This may, in time, open the door not only for advanced MRI but also for
other biomedical applications, such as cancer hyperthermia therapy, the imaging
and treatment of strokes, the detection and cleaning of blocked blood vessels, as
well as micro - and even nano - surgery. All of these aspects will undoubtedly
have great value in the further development of nanomedicine.
4.6
Summary and Future Outlook
In this chapter, we have outlined the depth and breadth of current research into
the synthesis, stabilization and functionalization of aqueous magnetic nanopar-
ticle and nanocomposite suspensions, although the survey was far from exhaus-
tive. An outline has also been provided of the methods currently used by the
materials research community in the development of these novel materials, and
of the major issues facing the imaging community. The next challenge for these
two communities is to exploit the potential of novel magnetic materials for bio-
medical applications. In the fi rst instance, the focus is likely to be on the develop-
ment of new magnetic materials to analyze the fate of biological markers in
tissues, and even at a cellular level, in model systems. These methods will be criti-
cal to biologists, pharmacologists, and clinicians in the development of new thera-
peutic interventions.
The future of clinical MRI is, in part, dependent on the development of new
contrast media. Whilst all indications suggest that nanoparticulate agents will
continue to be important; there is a strong belief that their potential has only been
partially realized. Among the applications with strong potential that have received
huge attention are the use of particles in dynamic (or time-resolved) imaging and
the development of smart and/or multifunctional agents. The latter are materials
for which the magnetic properties depend on their biological environment, and
which may combine multiple diagnostic functionalities and drug delivery
capability.
There are, in principle, three ways to improve the performance of an agent in
providing image contrast: (i) to improve the imaging hardware; (ii) to introduce
new experiments and pulse sequences to exploit the properties of the agents; and
(iii) to improve the characteristics and functionality of the agent itself. In the sec-
tions below, we will provide some brief examples of the fi rst two types of innova-
tion, before concentrating on new agents. The future of this research remains very
open to unforeseen changes, while even the division of likely innovations into
these approaches is arbitrary, as new applications may well embody some aspects
of all three. Nonetheless, it is useful to survey relevant current research, as it may
be indicative of the future direction of contrast agent development.
